壳聚糖微球悬浊液的介电谱研究:弛豫机制的解释和内部信息的获得

Dielectric Spectroscopy Study on Chitosan Microsphere Suspensions: Interpretation of Relaxation Mechanism and Obtainment of Inner Information

结合DLVO理论和壳聚糖微球的特点,提出了适合实验数据的电动力学模型,并分析了浓厚分散系的界面极化弛豫的微观机制.进而测量了不同粒径壳聚糖微球悬浊液的介电谱,发现在10～100MHz频率范围内均出现明显的介电弛豫现象.利用上述模型合理解释了该弛豫现象以及微球粒径对界面极化弛豫的影响,结果也证明了我们提出的模型的适当性.此外,利用Hanai方法,通过介电参数准确计算出了各悬浊液的内部信息,并且分析了这些实时信息的合理性.研究结果从实验和理论两方面展示了介电谱方法在即时获取壳聚糖内部信息上的独到优势.

By combining DLVO theory with the properties of chitosan microsphere, a suitable electrokinetic model was proposed, and the microscopic mechanism of interfacial polarization relaxation for concentrated suspensions was analyzed. Then dielectric measurements were carded out on concentrated suspensions of chitosan microsphere with different radius. Distinct dielectric relaxations were observed in the frequency between 10 and 100 MHz. By means of the model we proposed, the dielectric relaxation phenomena were satisfactorily interpreted and the effect of particle＇s radius on interfacial polarization relaxation was discussed. The results indicated that the model is suitable for the present systems. What is more, in light of the Hanai＇s method, the inner phase information of the suspensions was accurately calculated from dielectric parameters. The real time information was further analyzed to be reasonable. The results proved both ex- perimentally and theoretically that dielectric spectroscopy is rather effective in on-line obtaining inner phase information of chitosan.